many kernels in pmaports provides/replaces linux-headers

e.g. https://gitlab.postmarketos.org/postmarketos/pmaports/-/blob/master/main/linux-postmarketos-allwinner/APKBUILD#L83

This doesn't seem right, but I'm not really sure what the right thing to do here is..

But it leads to some weird situations where the wrong kernel headers/dev package is identified by apk, e.g. here's on my L5:

librem5:~$ apk search linux-headers
linux-postmarketos-allwinner-dev-5.13.1_git20210707-r0